Chronic fatigue syndrome - An update

The chronic fatigue syndrome is characterised by a fatigue that is dispropo rtionate to the intensity of effort that is undertaken, has persisted for 6 months or longer and has no obvious cause. Unless there has been a long pe riod of patient or physician- imposed inactivity, objective data may show l ittle reduction in muscle strength or peak aerobic power, but the affected individual avoids heavy activity. The study of aetiology and treatment has been hampered by the low disease prevalence (probably <0.1% of the general population), and (until recently) by a lack of clear and standardised diagn ostic criteria. It is unclear how far the aetiology is similar for athletes and nonathletes. It appears that in top competitors, overtraining and/or a negative energy balance can be precipitating factors. A wide variety of ot her possible causes and/or precipitating factors have been cited in the gen eral population, including psychological stress, disorders of personality a nd affect, dysfunction of the hypothalamic-pituitary-adrenal axis, hormonal imbalance, nutritional deficits, immune suppression or activation and chro nic infection. However, none of these factors have been observed consistent ly. The prognosis is poor; often disability and impairment of athletic perf ormance are prolonged. Prevention of overtraining by careful monitoring see ms the most effective approach in athletes. In those where the condition is established, treatment should aim at breaking the vicious cycle of effort avoidance, deterioration in physical condition and an increase in fatigue t hrough a combination of encouragement and a progressive exercise programme.